Electronics. Of a circuit, device, or program: designed to indicate or respond to the state of a telephone line, power supply, or other electrical or electronic system.
1978 Sci. Amer. Mar. 61/2 (caption) Supervisory and switching circuits in the central office connect the two sets for the conversation and disconnect them when the call is over.
Google Books (searching for this and "switchboard" together):
SUPERVISORY CONTROL A miniature switchboard is used to provide centralized control of the operations of the station . This supervisory board is centrally located on the generator floor between units 4 and 5.
By American Institute of Electrical Engineers · 1931
Willow Creek Pumping Plant
The supervisory board is designed to match in general appearance the motor control switchgear.
The Colorado-Big Thompson Project
Constructed 1938-56 : Technical Record of Design and Construction
By United States. Bureau of Reclamation · 1957
A system supervisory board named the system console ( SYSCSL ) is installed to provide a means of transmitting various information from the system to maintenance personnel
International Switching Symposium. October 25-29, 1976, Kyoto, Japan